Rechargeable batteries are now widely used for many portable electronic devices including laptop computers, "Walkman".RTM. type tape and compact disk players, and cellular radiotelephones. The use of rechargeable batteries allows an electronic device to be used without the need for a plug-in power source. In addition, the rechargeable battery can be recharged and used again when the charge of the rechargeable battery is depleted thereby reducing the expense of purchasing new batteries every time the batteries are depleted. The use of rechargeable batteries is discussed, for example, in U.S. Pat. No. 4,851,756, U.S. Pat. No. 5,418,433, and U.S. Pat. No. 4,667,142.
In particular, rechargeable batteries for use with portable radiotelephones can provide low internal impedance and high storage capacity. These batteries, however, may suffer from self-discharge wherein the rechargeable battery may discharge itself completely within a few weeks even if the radiotelephone has not been used. This self-discharge may be particularly troublesome for casual-use radiotelephone subscribers.
Because of self-discharge, a casual-use subscriber may often find that the battery is dead even though the radiotelephone has not been used since the batteries were last recharged. Carrying a second rechargeable battery may not remedy this problem because the second battery may self-discharge in roughly the same time as the first rechargeable battery. Accordingly, the self-discharge of rechargeable batteries may reduce the usefulness of portable radiotelephones for casual-use subscribers. This problem may increase as the number of casual-use subscribers continues to grow.
Accordingly, there exists a need in the art for battery packs, electronic devices, and methods which reduce problems resulting from the self-discharge of a rechargeable battery.